Railway vehicle bogie, associated vehicle and axle installation method

ABSTRACT

A bogie for a railway vehicle includes a frame, at least one axle, at least one axle box internally receiving the at least one axle, and a suspension of each axle box on the frame. The suspension includes an arm supporting the axle box and at least one elastic member interposed between the arm and the frame. The frame includes a cavity for receiving each elastic member. The cavity includes an opening and a bottom. An upper end of the elastic member is engaged in the cavity through the opening and bears on the bottom.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to French Patent Application No. FR 2009647 filed on Sep. 23, 2020, the disclosure of which including thespecification, the drawings, and the claims is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a railway vehicle bogie, comprising:

-   -   a frame;    -   at least one axle;    -   at least one axle box, internally receiving the at least one        axle;    -   a suspension of the or each axle box on the frame; the        suspension comprising:    -   an arm supporting the axle box; and    -   at least one elastic member interposed between the arm and the        frame.

BACKGROUND OF THE INVENTION

Railway vehicle bogies are adapted to hold axles that are rotationallymobile relative to a vehicle body. Railway vehicle bogies are furtheradapted to ensure the comfort of users within the vehicle body and/or toensure the durability of the vehicle body's structure by absorbingshocks transmitted from the axles to the vehicle body.

For this purpose, railway vehicle bogies may comprise a frame and an armsupporting an axle box, the axle being rotatably guided relative to theaxle box and the movement of the arm being damped relative to the frame.In particular, at least one elastic member connects the arm and theframe, with the spring assembly(-ies) ensuring a damped transmission ofshocks from the axle to the vehicle body.

In order to achieve a high degree of damping while limiting the verticalspace requirement, it is possible to use long springs, extending forexample to the front or rear of the axle box and being supported on alower part of the axle box, arranged below the axis of rotation of theaxle.

However, such a solution is not entirely satisfactory, as it is thencomplicated to fit or remove an axle from the axle box, since a largepart of the bogie, and in particular the spring assemblies, would haveto be removed.

SUMMARY OF THE INVENTION

One aim of the invention is therefore to provide a bogie with a smallvertical footprint and high damping characteristics.

To this end, the invention relates to a vehicle bogie of theaforementioned type in which the frame comprises, for the or eachelastic member, a cavity for receiving said elastic member, the cavitycomprising an opening and a bottom, an upper end of the elastic memberbeing engaged into the cavity through the opening and bearing on thebottom.

A bogie in which the frame comprises a spring receiving cavity for eachelastic member is particularly advantageous, as it allows theinstallation of long springs in a suspension with limited verticalspace.

According to particular embodiments of the invention, the railwayvehicle bogie also has one or more of the following features taken inisolation or in any combination that is technically possible:

-   -   the arm comprises at least one bearing region offset        longitudinally forwards or rearwards with respect to the axle,        the at least one elastic member having a lower end bearing on        the at least one bearing region;    -   the bearing region extends vertically between a central axis of        the axle and a vertex of the axle box;    -   the bogie comprises a joint connecting the arm to the frame, the        arm preferably being rotatable relative to the frame about the        joint;    -   the axle box comprises an upper body and a lower body detachably        connected to the upper body;    -   the arm defines the upper body;    -   the frame comprises a hollow spar bounded by an upper wall and a        lower wall, the opening being formed in the lower wall and the        cavity extending into the hollow spar;    -   the bottom is offset vertically upwards from the opening, the        bottom being defined by the upper wall; and    -   the bogie comprises two elastic members, a first elastic member        bearing on a bearing region offset longitudinally forwards with        respect to the axle, and a second elastic member bearing on a        bearing region offset rearwards with respect to the axle.

The invention further relates to a railway vehicle comprising at leastone bogie as aforesaid.

BRIEF DESCRIPTION OF THE DRAWING

Further features and advantages of the invention will become apparentfrom the following description, which is given by way of example onlyand is made with reference to the attached drawing, in which the thesingle Figure is a schematic representation in longitudinalcross-section of a bogie according to the invention and moreparticularly of the primary suspension extending between the axle boxand the bogie frame.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, the terms “top” and “bottom” or “lower” and “upper”are used to refer to the vertical direction of the railway vehicle. Theterms “front”, “rear” and “longitudinal” refer to the longitudinaldirection of the railway vehicle.

With reference to the figure, a railway vehicle 10 comprises a bogie 14.The railway vehicle 10 further comprises a vehicle body mounted on thebogie 14 (not shown).

The railway vehicle 10 is for example a car designed to run on rails.The railway vehicle 10 is for example a locomotive or a car of atramway, a metro or a railcar.

The bogie 14 comprises a frame 22, at least one axle 12, at least oneaxle box 24 internally receiving the at least one axle 12, and asuspension of the axle box on the frame 22.

The axle 12 comprises a body 15, and wheels (not shown) mounted on thebody 15.

The body 15 is typically rotatable about a transverse axis of rotationC-C′.

A part 16 of the axle body 15 is received in the axle box 24.

The axle box 24 typically has a connection 20, such as a bearing, whichguides the axle body 15 in rotation about the axis of rotation C-C′relative to the frame 22.

The suspension comprises an arm 26, a joint 28 connecting the arm 26 tothe frame 22, and at least one elastic member 30. The bogie 14preferably further comprises a damper (not shown).

The frame 22 comprises a cavity 34 for receiving the or each elasticmember 30. In the example shown, the frame 22 comprises a first cavity35 and a second cavity 36.

Each cavity 34 comprises an opening 37 and a bottom 38.

Each bottom 38 mates with an elastic member 30. In particular, an upperend of the elastic member 30 is engaged in the cavity 34 through theopening 37 and rests on the bottom 38. The opening 37 is offset from thebottom 38. The bottom 38 is for example vertically offset upwards fromthe opening 37.

The opening 37 extends for example in a plane parallel to a plane inwhich the bottom 38 extends. The opening 37 is for example circular inshape.

In the embodiment shown in the figure, the frame 22 comprises a hollowlongitudinal member 40.

The hollow spar 40 comprises, and is bounded by, a lower wall 42 and anupper wall 44. The hollow spar 40 preferably extends in the longitudinaldirection.

In a particular embodiment, the hollow spar 40 comprises at least threereinforcements 46.

The lower wall 42 and the upper wall 44 form, for example, elongatedplates in the longitudinal direction extending substantially parallel toeach other.

The lower wall 42 is, for example, a metal sheet with a thickness ofbetween 12 mm and 20 mm.

The upper wall 44 extends substantially horizontally, for example. Thelower wall 44 is, for example, a metal sheet with a thickness of between10 mm and 18 mm.

The distance between the upper wall 44, and more particularly the top ofthe upper wall 44, from the axis of rotation C-C′ is for example between350 mm and 410 mm.

Each reinforcement 46 extends between the lower wall 42 and the upperwall 44 and connects the lower wall 42 and the upper wall 44. Eachreinforcement 46 extends substantially vertically, for example. Eachreinforcement 46 is, for example, a metal sheet with a thickness ofbetween 10 mm and 16 mm.

According to the embodiment shown in the figure, the opening 37 of thecavity 34 is formed in the lower wall 42 and the bottom 38 of the cavity34 is defined by the upper wall 44.

The reinforcements 46 in such a case advantageously define an internalcontour of the cavity 34 connecting the opening 37 to the bottom 38 ofthe cavity 34.

In a particular embodiment (not shown), the walls 42, 44 and thereinforcements 46 defining the cavity 34 are formed from the same part,for example moulded. In the example with two cavities 35 and 36, the twocavities can advantageously be made of one or two castings (or any otheradvantageous combination of castings, forgings or flat products).

In one particular embodiment, the frame 22 includes a first stop region49, adapted to contact the arm 26 and limit the movement of the arm 26relative to the frame 22.

The joint 28 connects the arm 26 to the frame 22. In particular, thejoint 28 is adapted to allow rotation of the arm 26 relative to theframe 22, preferably over a rotation range of less than ±6°.

The arm 26 comprises an upper side 51 facing the frame 22, and a lowerside 50 opposite the upper side 51.

The arm 26 comprises a free end 52 opposite a connection end 54, atwhich connection end 54 it is connected to the frame 22 by the joint 28.The arm 26 extends between the free end 52 and the connection end 54.The arm 26 is preferably elongated between the free end 52 and theconnection end 54, i.e. the large dimension of the arm 26 extendssubstantially along the direction formed between the free end 52 and theconnection end 54.

The arm 26 comprises at least one bearing region 58.

The or each bearing region 58 is preferably formed on the upper side 51of the arm 26. The or each bearing region 58 is in particular formedopposite an opening 37 of a cavity 34.

The or each bearing region 58 is offset longitudinally forwards orrearwards relative to the axle box 24.

In the embodiment shown in the figure, the arm 26 comprises a forwardlyoffset bearing region 62 and a rearwardly offset bearing region 60relative to the axle box 24. In this embodiment, the rear bearing region60 is offset towards the connection end 54; and the front bearing region62 is offset towards the free end 52.

Each bearing region 58 mates with an elastic member 30. In particular,the elastic member 30 has a lower end abutting one of or the bearingregion 58.

Each bearing region 58 extends for example substantially in a horizontalplane. Each bearing region 58 preferably extends vertically at orslightly above the axis of rotation C-C′ of the axle 12 relative to thebogie 14. Each bearing region 58 extends in particular between thecentral axis C-C′ and a vertex 63 of the axle box. The vertex 63 of theaxle box 24 is the highest region of the axle box 24.

The arm 26 comprises for example a second stop region 65, arrangedopposite the first stop region 49 and adapted to contact the second stopregion 49, in particular to limit the movement of the arm 26 towards theframe 22. The second stop region extends for example longitudinallybetween the rearwardly offset bearing region 60 and the forwardly offsetbearing region 62.

The arm 26 carries the axle box 24 and, in one particular embodiment,forms a portion of the axle box 24.

The axle box 24 preferably comprises an upper body 66 and a lower body68. The axle box 24 preferably comprises means for fixing 70 the lowerbody 68 to the upper body 66.

The lower body 68 is connected to the upper body 66. In particular, thelower body 68 is attached to the upper body 66 by removable fasteningmeans 70, the fastening means 70 being screws for example. When thefastening means 70 are removed, the lower body 68 is for exampleremovable.

The upper body 66 extends above the connection 20. The upper body 66 isadapted to support the force applied by the railway vehicle 10 on theaxle 12.

The upper body 66 comprises for example an inner face 72 for mating withthe connection 20. The inner face 72 is for example in the shape of aportion of a cylinder, and more particularly in the shape of ahalf-cylinder.

The upper body 66 is preferably defined by the lower face 50 of the arm,a portion of the lower face 50 of the arm then forming the inner face 72of the upper body 66.

The lower body 68 is for example formed by a concave part and comprisesan inner face 74 intended to mate with the connection 20. The inner face74 is for example in the shape of a portion of a cylinder, and moreparticularly in the shape of a half-cylinder.

The at least one elastic member 30 comprises at least one spring 76.

In the embodiment shown in the figure, the bogie comprises two elasticmembers 30, a first elastic member 78 comprising two concentric springs76 and a second elastic member 80 comprising only one spring 76.

Each spring 76 comprises a lower end 82 and an upper end 84. In theembodiment shown, each elastic member 30 comprises an upper saddle 48and a lower saddle 64. The upper 48 and lower 64 saddles have at leastone ring, onto which the upper 84 and lower 82 ends of the spring 76,and a pin projecting from the centre of the ring and engaging the spring76, are supported. The upper saddles 48 are attached at the bottoms 38and the lower saddles 64 are attached at the bearing regions 58.

With reference to the figure, the first elastic member 78 is supportedon the bearing region 62 offset longitudinally forward with respect tothe axle box 24 on the one hand and on the bottom 38 of the first cavity35 on the other. The second elastic member 80 is supported on thebearing region 60 offset longitudinally rearward with respect to theaxle box 24 on the one hand and on the bottom 38 of the second cavity 36on the other. The axle box 24 is thus arranged longitudinally betweenthe first elastic member 78 and the second elastic member 80.

Typically, the springs 76 are helical springs.

Each spring 76 preferably has between 3 and 8 active coils andpreferably between 3 and 6 active coils.

The stiffness of each spring 76 is preferably between 200 N/mm and 500N/mm for the first elastic member 78 and between 900 N/mm and 1,200 N/mmfor the second elastic member 80.

The length of each spring 76 is generally not the same for springs ofthe first elastic member 78 as for those of the second elastic member80.

The length of each spring 76 is always greater than 220 mm when thesprings 76 are installed in the bogie 14. In particular, the length ofeach spring 76 is between 220 mm and 360 mm when the springs areinstalled in the bogie 14. The uncompressed length of each spring is forexample 425 mm.

The length of each spring 76 of the first elastic member 78, when thespring 76 is installed in the bogie 14, is for example between 300 mmand 360 mm and the length of each spring 76 of the second elastic member80, when the spring 76 is installed in the bogie 14, is for examplebetween 220 mm and 300 mm.

In the embodiment in which the frame 22 comprises a first stop region 49and the arm 26 comprises a second stop region 65, the length of eachspring 76 is minimal when the first stop region 49 contacts the secondstop region 65.

The damper (not shown) is for example connected to the frame 22 on theone hand and to the arm 26 on the other. In particular, the damper isadapted to dampen movements of the arm 26 relative to the frame 22. Thedamper is for example arranged longitudinally between the first elasticmember 78 and the second elastic member 80.

A method of installing an axle 12 in a railway vehicle bogie 14 aspreviously described will now be described.

In a supply step, a bogie 14 as described above is provided.

In an installation step following the supply step, the axle 12 isinstalled in the axle box 24. In particular, the lower body 68 isdetached from the upper body 66 and the axle 12 is positioned relativeto the bogie 14. The connection 20 is for example installed around theaxle 12, and the axle with the connection 20 is installed in the upperbody 66, for example in contact with the inner face 72 of the upper body66. The lower body 68 is then brought around the axle 12, and moreparticularly around the connection 20, the lower body 68 and the upperbody 66, thus clamping the axle 12 and the connection 20.

In an attachment step following the connecting step, the lower body 68is attached to the upper body 66 to form the axle box 24 around the axle12 installed in the upper body 66. The lower body 68 is, for example,attached to the upper body 66 via the fastening means 70. The fasteningmeans 70 are for example detachable, the lower body 68 thus beingremovable from the upper body 66, in particular to allow replacement ofthe axle 12 or part of the axle 12.

A frame 22 comprising, for the or each elastic member 30, a cavity 34for receiving said elastic member 30 allows the use of long springs 76without complicating the installation of axles 12 on the bogie 14, whilelimiting the vertical bulk of the bogie 14.

The use of an arm 26 defining the upper body 66 of the axle box 24 and alower body 68 connected to the upper body 66 is particularlyadvantageous in facilitating the installation of an axle 12 in the bogie14, the axle 12 then being able to be installed and/or uninstalled bysimply fitting/removing the lower body 68 around the connecting portion20.

A frame 22 comprising a hollow spar 40 defining the cavity 34 isparticularly advantageous as it allows a significant portion of thelength of the elastic members 30 to be accommodated (for example between30% and 50%).

The position of the bearing region 58 is particularly advantageous inachieving a long spring length 76 while allowing the use of a lower body68 which can be easily removed to facilitate installation of the axle onthe bogie 14 or removal of the axle 12 from the bogie 14.

The use of two spring assemblies 30 is particularly advantageous as itallows the use of space-saving springs 76 and limits the force appliedto the joint 28.

What is claimed is:
 1. A bogie for a railway vehicle, comprising: aframe; at least one axle; at least one axle box, internally receivingthe at least one axle; a suspension of the or each axle box on theframe; the suspension comprising: an arm supporting the axle box; and atleast one elastic member interposed between the arm and the frame;wherein, the frame comprises, for the or each elastic member, a cavityfor receiving said elastic member, the cavity comprising an opening anda bottom, an upper end of the elastic member being engaged in the cavitythrough the opening and bearing on the bottom, and wherein the bogiecomprises two elastic members, a first elastic member bearing on abearing region offset longitudinally forwards with respect to the axle,and a second elastic member bearing on a bearing region offset rearwardswith respect to the axle.
 2. A bogie for a railway vehicle according toclaim 1, wherein the arm comprises at least one bearing region offsetlongitudinally forwards or rearwards relative to the axle, the at leastone elastic member having a lower end bearing on the at least onebearing region.
 3. A bogie for a railway vehicle according to claim 2,wherein the bearing region extends vertically between a central axis ofthe axle and a vertex of the axle box.
 4. A bogie for a railway vehicleaccording to claim 1, wherein the bogie comprises a joint connecting thearm to the frame.
 5. A bogie for a railway vehicle according to claim 4,wherein the arm is rotatable relative to the frame about the joint.
 6. Abogie for a railway vehicle according to claim 1, wherein the axle boxcomprises an upper body and a lower body removably connected to theupper body.
 7. A bogie for a railway vehicle according to claim 6,wherein the arm defines the upper body.
 8. A bogie for a railway vehicleaccording to claim 1, wherein the frame comprises a hollow spar boundedby a lower wall and an upper wall, the opening being formed in the lowerwall and the cavity extending into the hollow spar.
 9. A bogie for arailway vehicle according to claim 8, wherein the bottom is verticallyupwardly offset from the opening, the bottom being defined by the upperwall.
 10. A railway vehicle comprising at least one bogie according toclaim 1.